If we took as a baseline that Europeans have an average of 3.5 percent Neandertal, Ötzi would have around 5.5 percent (again, the actual percentage would be highly model-dependent). He has substantially greater sharing with Neandertals than any other recent person we have ever examined.

In the end, the book comes up with the following personality traits for Neanderthals. Pragmatism, based primarily on the evidence for gastronomic cannibalism. Stoicism and Bravery, based on the danger of their lifestyle and the evidence of persistent injuries. Sympathy, based on the fact that there are Neanderthal skeletons that appear to have lived long after being seriously injured to the point of disability, implying that they were cared for by loved ones. Callousness, however, was in their nature as well; while there are upper body injuries in people who were looked after, there aren’t any lower body injuries that had healed, and the authors suggest that if you couldn’t move with the tribe then you weren’t cared for.

I wonder how he chose 3.5% as a baseline - 23andme reports 2.1% average in their userbase, and pegs me at 98th percentile with 3.1%. It looks like their 50th percentile for Northern European users is somewhere around 2.5%.

If I understand correctly, however, none of that undermines the central point, which is that Otzi has an unexpectedly high percentage of Neandertal DNA, meaning maybe what we are calling Neandertal DNA might not be.posted by mwhybark at 2:26 PM on August 18, 2012

no, i think i am missing the point. i do not understand the debate.posted by mwhybark at 2:30 PM on August 18, 2012

I'm not sure there's a debate. I think it's just an interesting finding, that this dude from 5300 years ago had quite a bit more Neandertal DNA in him than your average contemporary human of European descent. It doesn't necessarily tell us a lot all on its own but it raises some great questions, most of which boil down to "Why?"

Which I assume is what we are now working on.posted by Scientist at 2:49 PM on August 18, 2012

As far as I can tell, the scientific debate is about why European and Asian humans have Neandertal DNA, and African humans don't. Either humans and Neandertals interbred after humans left Africa, or those humans who left Africa were of lineages that still held a lot of ancestral DNA in common with Neandertals. Paabo and Reich hold the former view; the PNAS paper holds the latter view. Basically, the question is whether there was interbreeding with Neandertals after our divergence from them.

But a lot of what John Hawks (and people he linked to) seems to be upset about is getting geneticists to use pre-print servers, and frankly that part of the debate is really confusing and makes me feel angry without quite knowing why. It feels like they're attacking the PNAS paper for not posting to arXiv ("Dude, if you'd posted it to arXiv I coulda told you you were wrong") but also saying that the PNAS paper didn't use data that was freely available to them...? It feels like Reich is throwing a temper tantrum, somehow. I want to make him sit in a corner until he can come up with a coherent criticism.posted by Made of Star Stuff at 2:52 PM on August 18, 2012 [2 favorites]

(Also, apparently it's not even true that "Africans don't have Neandertal DNA," since Reich reports that his lab has found a few individuals with very high amounts of Neandertal DNA -- and he's being agnostic about where they got it from. Messy stuff!)posted by Made of Star Stuff at 2:53 PM on August 18, 2012

The guy says, "our comparisons quickly refute the hypothesis that Neandertal similarity comes only from ancient population structure in Africa."

There's a debate. I don't understand it. Not like, "Why are you fighting stop it" don't understand, more like "i need some to explain things to me at a lower level because i am a caveman" don't understand.posted by mwhybark at 2:55 PM on August 18, 2012 [1 favorite]

I don't know enough about the subject to know how much debate there is about African-Neandertal DNA. The conflict presented in Hawks' blog is that some other researchers are building Neandertal ancestry models without referencing the latest data. Hawks is performing studies on the Ötzi genome, and wonders why more researchers aren't doing the same.posted by b1tr0t at 3:02 PM on August 18, 2012

I think you've got the gist of it about right, though, Star Stuff.posted by Segundus at 3:04 PM on August 18, 2012

I wonder how he chose 3.5% as a baseline - 23andme reports 2.1% average in their userbase, and pegs me at 98th percentile with 3.1%. It looks like their 50th percentile for Northern European users is somewhere around 2.5%.

From the article:

Another example is the proportion of Neandertal ancestry. Initially, the proportion of ancestry from Neandertals in living people was argued to be between 1 and 4 percent [3]. That was a model-based estimate that was the best possible under the assumption that Africans have no Neandertal ancestry. We now have a lot more human comparisons, which would make possible a more precise estimate of the mean. I hesitate to provide a new estimate, because we have shown that some Africans have substantial evidence of Neandertal similarity, which throws the baseline for any estimate into question. How much Neandertal ancestry is present in living people must depend on a more complex model of mixture among later populations. The result will still be small (probably less than 6 percent) but understanding this proportion will help us to evaluate when and where Neandertal genes flowed into our populations.posted by francesca too at 3:05 PM on August 18, 2012

Look, obviously Neanderthals preferred to hook up with the Eurasian folks instead of the African cavepeople because the Eurasians were sexy time-traveling astronauts with weapons. There's no contest here.

Unless the Neanderthals were the time-traveling astronauts who crash-landed in Africa, then shrugged stoically and settled down to live happily ever cave-sexytimes after. But not before hiding the Statue of Liberty in the fossil record to mess with our heads.posted by nicebookrack at 3:30 PM on August 18, 2012 [2 favorites]

I think Hawks's problem with the PNAS paper is that it shuffles around existing data with new models, as opposed to testing the models on data they weren't tuned to. I think his point in bringing up Otzi is that the Neandertal ancestry sticks out even when you try many different models.

What I find most interesting in this result is that there may have been more Neandertal genes around at a time not so long ago. Were the characters in The Iliad more Neandertal than anyone alive today? It's hard to point to natural selection effects in historical times, other than maybe lactose tolerance. Were those extra Neandertal genes Otzi had useful in Europe from 35,000 to 5,300 years ago, but disadvantageous after that? Or did populations just get more mixed and Neandertal contributions more diluted?

Or was Otzi not typical of southern Europeans 5,300 years ago?posted by Schmucko at 3:46 PM on August 18, 2012

Seems like the population boom since Otzi's time combined with Neandertals being extinct by then would be more than enough to dilute the Neandertal DNA a few more percent.

Naturally I am not going to do any math or difficult thinking to back that up.posted by TheRedArmy at 3:50 PM on August 18, 2012 [2 favorites]

That's all pretty interesting, but I'm rather more curious about the downstream questions of what the practical impact of the Neanderthal-genes-in-humans are. Are they ever expressed? What do they do, if anything? Do they affect any disease resistance/vulnerability? Affect any observable traits? I realize we're still in the medieval stages of understanding how genes operate, but perhaps there may already be some hints along the lines of "people with this SNP genotype variation have higher rates of fubar" whatever.posted by VikingSword at 3:50 PM on August 18, 2012 [2 favorites]

The specific gene HLA-A, for example, is present in the Neanderthal and Denisovan genomes. It contributed this much to the following modern human populations: Up to 95.3 percent for Papua New Guineans, 80.7 percent for Japanese people, 72.2 percent for Chinese people, 51.7 percent for Europeans, and 6.7 percent for Africans.

Thanks for the article, Schmucko. One thing that I always wondered is if humans interbreeding with other hominids wasn't a roundabout way of increasing diversity. The idea being that the populations that left Africa for other continents had less genetic diversity initially, compared to the great diversity of the human populations that were left in Africa. But a lack of diversity can produce vulnerabilities and less adaptability - so one way in which the populations that spread out of Africa could increase diversity was by the genetic contributions of other hominids.posted by VikingSword at 4:14 PM on August 18, 2012

Also, apparently it's not even true that "Africans don't have Neandertal DNA," since Reich reports that his lab has found a few individuals with very high amounts of Neandertal DNA -- and he's being agnostic about where they got it from.

Right. It could be that when some of the populations that left Africa then came back after interbreeding with Neanderthals, they could then introduce the Neanderthal genes to some African populations. According to the article Schmucko linked above, that would have been sometime about 10,000 years ago - and it was not just European, but Asian populations.posted by VikingSword at 4:20 PM on August 18, 2012

One thing that I always wondered is if humans interbreeding with other hominids wasn't a roundabout way of increasing diversity. The idea being that the populations that left Africa for other continents had less genetic diversity initially, compared to the great diversity of the human populations that were left in Africa. But a lack of diversity can produce vulnerabilities and less adaptability - so one way in which the populations that spread out of Africa could increase diversity was by the genetic contributions of other hominids.

I assume you mean unknowlingly? In that populations which did interbreed outlived those which did not through the good which interbreeding brought?posted by Jehan at 5:17 PM on August 18, 2012

In science, as in all things, there is contention. Not everyone is agreed on some of the details of these greater theories.

Also, archeologists (and anthropologists in general) tend to fall into two camps: splitters and joiners.

So, another way of looking at this is that "neanderthals" are really just relatively contemporary humans with typical climate phenotype expression. That is, there isn't a lot of strong evidence to support the notion that neanderthals were a separate species.

So, one can read this new evidence as simply some people insisting on interpreting the genetics in an incorrect manner.posted by clvrmnky at 5:19 PM on August 18, 2012 [2 favorites]

I assume you mean unknowlingly? In that populations which did interbreed outlived those which did not through the good which interbreeding brought?

Is there some way to ascertain the direction of adaptation? For example, isn't it possible, at least theoretically, that the hominid genes weakened rather than strengthened the hybrids? So that subsequent selection was for weeding out the non-sapiens genes. That might account for why contemporary humans have fewer Neanderthal genes than Otzi - in other words, rather than dilution being responsible, it would be active selection against. Or perhaps, given the random nature of selection, perhaps only those Neanderthal/hominid genes which conferred some advantage on the hybrids remained in humans, while all others were gotten rid of (or rendered inactive).posted by VikingSword at 5:47 PM on August 18, 2012

Do we still think Neanderthals may have had larger brains than modern humans? It'd kind of be a bummer if the smarter hominids got eated/killed off by us mean dummies or something.posted by floam at 6:07 PM on August 18, 2012

Do we still think Neanderthals may have had larger brains than modern humans? It'd kind of be a bummer if the smarter hominids got eated/killed off by us mean dummies or something.

Since Neandertals are a distinct and different spieces from us, does that technically mean that we (euro white people) are all the products of beastiallity?posted by wcfields at 6:25 PM on August 18, 2012

Has there ever been a time when humans weren't screwing everything that moved? I doubt it.posted by bleep at 7:09 PM on August 18, 2012

Spoiler alert: if you go back far enough in the evolutionary line, everyone including Europeans are descended from FOUR-LEGGED FURRY BLOBS who had sex with FOUR-LEGGED FURRY BLOBS. Forget bestiality, we're all thisclose to being fungi.

Not to mention the genetic bottlenecking a la mitochondrial Eve that means we're all having sex with our relatives. It's incest and bestiality and gonads and turtles all the way down!posted by nicebookrack at 7:13 PM on August 18, 2012 [8 favorites]

One thing to note is that the earliest archaelogical evidence of war dates to around 13,000 years ago, in the Nile Valley. Hominids were pretty good about avoiding conflict between groups before then. Neanderthals died out around 24000 years ago, ten millennia before the "innovation" of war... genocidal extinction is very unlikely, so you can stop feeling guilty about that, if you were so inclined.posted by Slap*Happy at 7:14 PM on August 18, 2012 [3 favorites]

But has anyone tested Ron Perlman?

The classic Perlman's Gambit: A dice tossed against Ron Perlman will tend towards Ron Perlman striking you again and again about the face with a strong tool, throwing flowers on your body and fleeing into the trees with his huntdogs to pursue a steady gig on a network procedural that will pay him in skins and tools.

African cavepeople because the Eurasians were sexy time-traveling astronauts with weapons

Wait, wait, will this finally bring closure to the heated and eternal Cavemen or Astronauts argument?posted by flaterik at 10:35 PM on August 18, 2012

This subject always makes me a bit squeamish, on account of how many people inevitably wonder aloud, What if Neanderthals were actually superior to humans?, without realizing that they might as well be asking, What if white people are actually superior to black people?

Just asking the question is bad enough. The fact that there are scientists devoting their careers to finding the answer is, frankly, not so awesome.posted by Sys Rq at 12:04 AM on August 19, 2012 [2 favorites]

I think Hawks's problem with the PNAS paper is that it shuffles around existing data with new models, as opposed to testing the models on data they weren't tuned to. I think his point in bringing up Otzi is that the Neandertal ancestry sticks out even when you try many different models.

Hawks' problem is that Hawks is a fully committed axe-grindy multiregionalist and has been for years, and so he starts grinding his axe whenever possible to advance his agenda against the single-origin folks, who vastly overwhelm the multiregionalists. Anthropolitics, in other words. Essentially: the single-originists say humans evolved once and didn't interbreed with archaic hominin species, while the multiregionalists say everyone was screwing everyone and humans came about from this intermingling all over the world, and there's terrible enmity between the two sides.

I'm formerly a paleoanthropologist myself, and while I haven't followed the literature for half a decade now my impression is that there has been some really compelling genetic evidence from Svante Pääbo's lab at the Max Planck Institute showing that yes, there was definitely interbreeding, but not (yet) to the level predicted by the multiregionalists. Hawks is rebutting a paper that is rebutting Pääbo's work. It's not shocking that Hawks would do this, because he is 1. outspoken and 2. a die-hard multiregionalist. I can't comment on the science here aside from saying the truth is probably somewhere in-between the two sides—i.e. that there was some interbreeding between species but humans likely evolved once or only in a few locales. I'm also not saying Hawks is wrong, and he definitely may be right—he's a really smart guy, and I'm too far out of the field—but he definitely has preconceived notions on this topic.

Also: paleoANTHROPOLOGIST. Not paleontologist. The latter studies non-human fossils. The former studies human origins.posted by The Michael The at 5:40 AM on August 19, 2012 [6 favorites]

John Hawks' posts on Denisova are some of the coolest things I have ever seen on the internet. These are about a newly discovered hominid found recently in Russia. His web literacy, writing and use of photos are a guide for just about everyone.

(The last I heard there were only a few bones and there is still some argument whether it is a different species than any of the previously identified ones.)posted by bukvich at 6:47 AM on August 19, 2012

Just asking the question is bad enough.

I think it's weird, but pretty okay, considering that none of the people asking this question are actually Neanderthals looking for new ways to systematically oppress humans as they have done for centuries.posted by elizardbits at 7:35 AM on August 19, 2012 [1 favorite]

http://blogs.discovermagazine.com/gnxp/2012/08/why-you-shouldnt-publish-in-pnas/
http://blogs.smithsonianmag.com/hominids/2012/08/neanderthal-and-human-matings-get-a-date/
http://content.usatoday.com/communities/sciencefair/post/2012/08/neanderthal-mating-debated-in-duelling-studies/1posted by stbalbach at 9:12 AM on August 19, 2012

This subject always makes me a bit squeamish, on account of how many people inevitably wonder aloud, What if Neanderthals were actually superior to humans?, without realizing that they might as well be asking, What if white people are actually superior to black people?

Personally,
(1) I think the paleoanthropological inquiry into human origins has nothing to do with "superior" and "inferior" which are coarse value judgments and not scientific findings
(2) At least according to Hawks's blog, there is evidence that not only Europeans and Asians mated with archaic hominids, but also some Africans, only the climate in those parts of Africa did not preserve the fossil record as well
(3) I've seen some research suggesting the brain development of Neandertals had very different timing of stages from modern humans, so that the way they thought might have been completely different from the way we think.
(4) The vast majority of our DNA appears to come from one branch that came from Africa (although it seems Hawks is arguing for substantial contributions from other lines). What was so great about that branch? Neandertals appeared to have our language gene. So maybe the timing of development was the novelty, and then we picked up some genes (mostly for immunity) from related branches along the way?posted by Schmucko at 1:55 PM on August 19, 2012 [1 favorite]

That's incredibly stupid.

Thank you ever so much for that well thought out response.
So there are forbidden, politically unacceptable questions.
Why?
Is it that we are afraid of answers to such questions?
We shouldn't be.

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